Transport refrigeration systems for straight trucks are often mounted through the front wall of the truck body. Tilt cab clearance is usually not a problem when the refrigerant compressor is in the truck engine compartment, and driven by the truck engine, as the refrigeration package mounted on the truck wall can easily be made small and compact. When a Diesel engine and compressor are added to the refrigeration package to make a self contained unit, however, it presents a challenge in coordinating and mounting the various refrigeration components on a frame to minimize the height of the refrigeration unit. Adding an optional standby electrical drive motor to the unit package, and the requirement that the unit intrusion into the truck cargo space be essentially zero, called "zero cube", additionally complicates the problem.
It is the object of the present invention is to provide a component layout for a completely self contained transport refrigeration unit suitable for a straight truck which, although it includes an evaporator, condenser, compressor and a prime mover, has a height dimension which will reduce or eliminate the need to increase truck body height to accommodate tilt cab clearance. It is a further object of the invention to locate the refrigerant evaporator within the frame of the transport refrigeration unit, with zero intrusion into truck cargo space, to provide a zero cube unit, notwithstanding that the prime mover includes an internal combustion engine and an optional electrical standby motor. It is an object of the invention to provide a zero cube unit having an evaporator air flow arrangement which promotes good air circulation through the cargo space of the associated truck. It is also an object of the invention to reduce the street level noise generated by the internal combustion engine.